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  • Acoustical Society of America (ASA)  (3)
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  • Acoustical Society of America (ASA)  (3)
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  • 1
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2006
    In:  The Journal of the Acoustical Society of America Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3283-3283
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3283-3283
    Abstract: k−space models for broadband acoustic pulse propagation differ from pseudo−spectral time domain (PSTD) models in their treatment of the time step. By replacing a finite−difference scheme with a propagator, exact for homogeneous media, larger time steps can be taken without loss of accuracy or stability and without introducing dispersion. Three k−space models for modeling photoacoustically generated (PA) pulses are described here. A very simple, exact, model of PA propagation in a homogeneous fluid is used to introduce the k−space propagator, and two models of propagation in heterogeneous media, originally designed for modeling scattering in soft tissue, are adapted for use in photoacoustics [Mast et al., IEEE Trans. UFFC 48, 341−354 (2001); Tabei et al., J. Acoust. Soc. Am. 111, 53−63 (2002)]. Our motivation for describing these models comes from biomedical PA imaging, in which one of the current limitations is the assumption that soft tissue has a uniform sound speed. Efficient, accurate, and simple−to−encode forward models such as these are very useful for studying the effects of the heterogeneities encountered in practice. They may also be useful in designing PA imaging schemes that can account for acoustic heterogeneities. [This work was funded by the EPSRC, UK]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2006
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2006
    In:  The Journal of the Acoustical Society of America Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3025-3025
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3025-3025
    Abstract: Biomedical photoacoustic (PA) imaging is a soft-tissue imaging modality that combines the high spatial resolution of ultrasound (US) with the contrast and spectroscopic opportunities afforded by imaging optical absorption. Exact reconstruction algorithms for PA imaging have been described for spherical, cylindrical, and planar sensor arrays. Many applications to date have used a cylindrical measurement geometry because a single US transducer may be scanned straightforwardly in a circle around a sample. However, planar US arrays composed of piezo or optical elements with small element sizes and fast acquisition times are readily available, making them an attractive option for imaging applications. To capture sufficient data for an exact PA reconstruction with a planar geometry requires an infinitely wide array. In practice, of course, it will be finite, resulting in a loss of resolution and introducing artefacts into the image. To overcome this limitation, it is proposed that acoustic image sources are used to generate a periodically repeating sound field that can be reconstructed exactly from measurements made over a finite aperture. [This work was funded by the EPSRC, UK]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2006
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2018
    In:  The Journal of the Acoustical Society of America Vol. 144, No. 4 ( 2018-10-01), p. 2061-2071
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 144, No. 4 ( 2018-10-01), p. 2061-2071
    Abstract: The image reconstruction problem (or inverse problem) in photoacoustic tomography is to resolve the initial pressure distribution from detected ultrasound waves generated within an object due to an illumination by a short light pulse. Recently, a Bayesian approach to photoacoustic image reconstruction with uncertainty quantification was proposed and studied with two dimensional numerical simulations. In this paper, the approach is extended to three spatial dimensions and, in addition to numerical simulations, experimental data are considered. The solution of the inverse problem is obtained by computing point estimates, i.e., maximum a posteriori estimate and posterior covariance. These are computed iteratively in a matrix-free form using a biconjugate gradient stabilized method utilizing the adjoint of the acoustic forward operator. The results show that the Bayesian approach can produce accurate estimates of the initial pressure distribution in realistic measurement geometries and that the reliability of these estimates can be assessed.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2018
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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